rainbow giant mealworms

SC Geckos

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Rainbow mealworms are (as far as I know) the same as Giant mealworms, They are common mealworms (Tenebrio molitor) that have been treated with an insect growth hormone to discourage them from morphing into beetles so they grow significantly larger. Some will still morph into beetles but they are sterile. So these mealworms can grow two or three times the size of a normal mealworm.

I have used them for fishing but I choose not to feed them to my animals because of the hormones they are given. I don't know if there would or could be any long term effect on my reptiles from the hormones, and don't want to chance it.
 

mtmountainman

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Rainbow mealworms are (as far as I know) the same as Giant mealworms, They are common mealworms (Tenebrio molitor) that have been treated with an insect growth hormone to discourage them from morphing into beetles so they grow significantly larger. Some will still morph into beetles but they are sterile. So these mealworms can grow two or three times the size of a normal mealworm.

I have used them for fishing but I choose not to feed them to my animals because of the hormones they are given. I don't know if there would or could be any long term effect on my reptiles from the hormones, and don't want to chance it.

I will email him and double check. Thanks for the heads up.
 

mtmountainman

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Here is the response I got.

The answer to your question is a bit complex but here goes:

All insects produce a hormone called Juvenile hormone. In insects that metamorphose into something else (like butterflies, beetles, etc.) they have a mechanism that stops the production of this hormone and that causes them to go into the pupae stage. All we do is keep their levels of hormone from dropping so that they won't pupate. ALL insects have this hormone, and it's not harmful to other species. In fact, the only chemical approved by the World Health Organization for use in water to control mosquitoes is made out of this hormone. It's specific only to insects, not other organisms.

If it were harmful to reptiles, then reptiles that eat insects that don't metamorphose (e.g. crickets, roaches) that have chronically high levels of this hormone, would have died off via evolutionary means long ago.

I hope this answers your question,

Thank you!
 

cassicat4

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Thanks for reporting the response. I, too, had heard they were injected with hormones to prevent them from pupating, but wasn't sure exactly what that entailed and never had a detailed description to go along with it. This is quite helpful.

They're also sold under the description of Kingworms. I, too, feed them to my water dragon and both of my Leos. I like that they have more bulk to them than regular mealworms. And they are harmless like mealworms as well.
 

mtmountainman

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I highly doubt they are injected. I'm sure they hormone is fed to them. If the mealworms naturally have this hormone already, I dont see the harm in giving them some to prevent them from pupating. Still not sure if I will feed them to my geckos or not though.
 

cassicat4

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I highly doubt they are injected. I'm sure they hormone is fed to them. If the mealworms naturally have this hormone already, I dont see the harm in giving them some to prevent them from pupating. Still not sure if I will feed them to my geckos or not though.

Sorry, let me clarify - I meant to say that prior to your post, I had thought (being told by others and not doing enough research myself to verify) they were injected with a hormone to stop their growth. Based on the response though, I agree that it doesn't sound like injection to me, but merely something they're fed.

Knowing that it's a natural hormone at work is reassuring as many other forums have people claiming that the hormones given to the worms is artificial which is where much of the fear comes from I believe.

If you do end up choosing to feed them, I find that my Leos really enjoy them, especially the fresh-moult white worms. Both of my Leos are adults though, so the size definitely isn't an issue.
 

SC Geckos

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Here is the response I got.

The answer to your question is a bit complex but here goes:

All insects produce a hormone called Juvenile hormone. In insects that metamorphose into something else (like butterflies, beetles, etc.) they have a mechanism that stops the production of this hormone and that causes them to go into the pupae stage. All we do is keep their levels of hormone from dropping so that they won't pupate. ALL insects have this hormone, and it's not harmful to other species. In fact, the only chemical approved by the World Health Organization for use in water to control mosquitoes is made out of this hormone. It's specific only to insects, not other organisms.

If it were harmful to reptiles, then reptiles that eat insects that don't metamorphose (e.g. crickets, roaches) that have chronically high levels of this hormone, would have died off via evolutionary means long ago.

I hope this answers your question,

Thank you!

That's cool that he took the time to explained this. I know that hormones are what control the morphing process and that they are natural, but I'm still not sure if the hormones that the insects are given are "natural" of a synthetic or if that even matters. I'm sure the seller knows a whole lot more about this than I do. lol!
They are quite a bit bigger than a normal mealie which is good, but I still don't like the idea of adding hormones. My thought is in the same way some doctors say foods we consume which have added hormones are not good for us in the long term, I sort of use that same thinking when it come to my geckos. (again JMO and not a fact) I guess the only other down fall with these worms (If the hormones are not an issue) is that you can not breed them which will require you to continue to buy them instead of producing them yourself like normal mealies or supers.
 

mtmountainman

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356
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Montana
That's cool that he took the time to explained this. I know that hormones are what control the morphing process and that they are natural, but I'm still not sure if the hormones that the insects are given are "natural" of a synthetic or if that even matters. I'm sure the seller knows a whole lot more about this than I do. lol!
They are quite a bit bigger than a normal mealie which is good, but I still don't like the idea of adding hormones. My thought is in the same way some doctors say foods we consume which have added hormones are not good for us in the long term, I sort of use that same thinking when it come to my geckos. (again JMO and not a fact) I guess the only other down fall with these worms (If the hormones are not an issue) is that you can not breed them which will require you to continue to buy them instead of producing them yourself like normal mealies or supers.

It is true that you would not be able to produce them yourself. But I get tired of buying 5,000 mealworms and tons of them turn into beetles before I can feed them all. It is nice that the giant mealworms don't pupate. Shortly my mealworm colony should be up and running and I will never have to buy any again.
 

SC Geckos

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It is true that you would not be able to produce them yourself. But I get tired of buying 5,000 mealworms and tons of them turn into beetles before I can feed them all. It is nice that the giant mealworms don't pupate. Shortly my mealworm colony should be up and running and I will never have to buy any again.

Oh, I agree. It was a pain when I first started my colony because for a while I was always stuck between either having beetles or tiny mealies not large enough to feed. Its nice once you get a good colony going. Mine colony has been going for about 7 years now.
 

mtmountainman

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Montana
Nice, too keep the baby mealworms the same size, I transfer a ton a beetles to a 6qt container with chicken mash and let them breed in there for a month before moving them to a knew one. I also have one large bin full of mixed mealworms an beetles and thats where I pull beetles from. I use to try to separate the different stages, but once I had half of a 5,000 mealworm order pupate, that got old fast haha.
 

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